I think it really boils down to, they need a near future myth for investors to speculate their stock price up. That myth is, ubiquitous, always-on AR is just around the corner, and they're going to be the platform it runs on.
And so the narrative changed, from:
"through the magic of {pixie dust technology} we can make providing chauffeur services so cheap it would be hugely profitable"
to
"we will replace all the human drivers with robots, any day now"
Of course, that future was much, much further away than purported, but it certainly was useful for pumping up optimism in a company where the present-day situation isn't necessarily favorable.
FB's money-printing products seem to be facing major headwinds. They're scandal-wracked, user growth is plateauing heavily especially in the most profitable markets, and a fast-moving competitor is rapidly eating into their most coveted growth areas and they seem unable to convincingly fight the trend. A narrative shift is certainly needed for them.
Uber literally just forecasted positive cash flow by the end of this year, and the stock tanked. FB banking on a far future R&D move is not likely to fly well with investors. Most certainly not in the near future.
I think it's both a function of investors having been burned in the recent past with unicorns failing to deliver on their lofty promises, but also the reality that FB has suffered significant (read: catastrophic) reputation damage from the endless stream of scandals. FB employees seem to have an inexhaustible belief that they can weather any storm without permanent harm, but I suspect that isn't actually true.
More than that, the narrative shift isn't convincing. At least with Uber they had fancy robot cars to show off, even if they didn't work. What does FB have to convince us of the metaverse future? A lot of expensive CGI-rendered "concept reels" and very little actual product that is actually here (or imminent). The recent Superbowl ad did not contain a single frame of actual product footage - nor did the "fake" product in any way resemble anything FB has announced!
And the little that does exist (Horizon Worlds) is... really... really... painfully bad. The fact that FB has even let the public at these experimental products (rather than iterate internally) is baffling.
As someone who's been in the consumer tech space for a really long time the strategy here is just mind-boggling. The company continues to pitch no actual product - it has remained frustratingly vague about what the metaverse even is - but also insist at the same time that the entire company is reorienting around it. What little is released is shockingly poor - to the point where one wonders if these half-baked products will poison the well against a better thought-out and genuinely useful product further down the line. It reeks not of visionary thought and more dragging whatever you can out of the experimental arm of the company to try to cement the narrative shift.
They needed a more exciting vision to continue to attract top talent, which is generally a prerequisite for a high stock price anyway.
If they execute on VR half as well as they did their core product than the hype is real
Yes, a story about the future that he wants to generate a collective social belief in.